A major aim of the proposed study is to extend current research on the effects of prolonged exposure to a particular physical environmental stressor, intense elevated subway train noise on African-American children's blood pressure, heart rate and health by assessing: 1) whether African-American children's blood pressure is related to or varies as a function of autonomic reactivity, parental history of hypertension, age and 2) whether other ethnic groups which experience similar environmental stressors and life experiences, that is, Latino preschool children, differ from African-American along these variable. Resting and stress-induced diastolic and systolic blood pressure of a prematched sample of 400 preschool-age children (200 African-American and 200 Latino) attending day care centers near and far from elevated subway trains will be measured. Absenteeism will be sued as an indirect measure of health. The results of the proposed study may broaden current noise theories and assist the government in setting public policies governing the legislation and control of suitable noise levels for home and school environments of young children.